There are known drivers, which are examples of such switching control circuits, applied for power devices; these power devices are widely applied for various machines. An example of these devices is disclosed in Japanese Patent Application Publication No. 2003-134797.
The Patent Publication discloses a gate driver for driving an IGBT (Insulated Gate Bipolar Transistor) as a target switching element to be controlled. The gate driver is comprised of a first MOSFET, a second MOSFET, and a soft turn-off MOSFET. The first MOSFET is connected to the gate of the target IGBT for turning on the target IGBT. The second MOSFET is connected to the gate of the IGBT for turning off the target IGBT. The first and second MOSFETs are connected to each other in series. The soft turn-off MOSFET is connected to the gate of the target IGBT, and connected to the second MOSFET in parallel thereto.
The gate driver operates normally to turn on the second MOSFET, thus turning off the target IGBT. When detecting that there is an abnormality in the target IGBT or its peripheral circuit, the gate driver turns on the soft turn-off MOSFET, thus slowly turning off the target IGBT.